Before Star Trek and following his career as a lawyer, Fields wrote several episodes for The Man from U.N.C.L.E., the show Deep Space Nine did a homage to with Del Floria's Tailor Shop being on Deep Space 9's promenade. Later, Fields was as an associate producer and writer on McCloud, an NBC series starring Diana Muldaur. Soon afterwards, he became a writer and executive story consultant for the popular ABC series The Six Million Dollar Man.

In addition to his work on Deep Space Nine, Fields worked with DS9 co-creator Michael Piller on the latter's short-lived UPN series, Legend (1995, starring John de Lancie). Other television shows for which Fields has written include Knight Rider (1986), Jake and the Fatman (1988), and Xena: Warrior Princess (1995-1996).